You might also have a problem with the Semaphore table file (EZSEMTAB.dat) in your data directory. It's purpose is to keep track of which user is doing what, and to warn if one user is preventing another from gaining access.

When nobody is accessing the data, try renaming this file (say the file extension) and it will automatically be created fresh the next time you start Adagio.
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I've also seen this error before (though not in the function you describe) when a workstation is pretty old with not a lot of memory, and also in the scenario Kate described with certain settings like Opportunistic Locking (or File Caching on Novell Client 32). You might want your I.T. person to give a hand.